General Information
Created for a certain type of XRT owner, and while we don't know you, this one's for the hooligans.
Direct Power:
The DP in the model number means this servo requires Direct Power. Anyway, this means it uses a 2S-4S pack. While we have them in capacities ranging from 650mAh to 6000mAh, the most popular pack is the B4S2500 and if you want one, then remember to add it to your order. Or select it from the pull-down menu under Power Options. Anyway, whether you buy a pack from us, or not, just so you know, the 2500 is the most popular size, and it uses an XT30 - keep this in mind.
Also, if you have other ideas for powering it, like maybe using a stand-alone BEC, perhaps a Castle Creations CC BEC 2.0 or similar (we have these, also), it's unlikely to have the stones to run the servo at full power.
Or if in the alternative, you're thinking of just tying into the propulsion pack, instead (maybe by tapping into two cells via the balance connector), then please be aware ripple (electronic noise) due to the motor/ESC (as it varies throttle position) will backfeed into the circuit (on the servo) and damage a component on the PCB. We're expressly warning against doing this so you know in advance that repair cost won't be covered by warranty. Not trying to be an asshat, but also don't want this to become a problem, so heads up, eh?
The DS188BLDP is made for an X-maxx and the -M version fits the XRT but to save you time, review this info for if you're curious because some of it may help guide you in your quest.
Q. I'm looking at buying the DS1885BLDP for my XRT. What is the power options all about? I am not sure what to select.
A. The DS1885BLDP servo is equipped with two connections instead of one. Reason for the second is due to being unable to make power out of thin air. Basically, when we get to this class of servo (the stock servo makes about 350oz-in vs 1885oz-in), then to keep from;
a) overwhelming the ability of a lands of the receiver's PCB to handle the current draw, and
b) the capability of an ESC's BEC circuit to create sufficient quantities of current, we resort to a trick.
We simply power the servo's control electronics (via the usual little black DuPont connector used for servos) by whatever powers the stock servo, and then we feed the servo motor with a dedicated source via an XT30 connector. So the servo has a 20AWG lead with a DuPont connector like usual, plus one more lead, a heavier one we quipped with an Amass XT30.
As for the source (a 4S battery pack), we offer two. One's small offering 850mA of capacity and the other (larger) outputs 2500mA, instead. The smaller one principally because there are some who heat race their rigs. These folks benefit from the lighter weight of the small pack. Most bashers get the larger pack.
And by way of heads up, please don't make the mistake of thinking, 'I can just tap into one of two propulsion packs to get the 4S power!' Please don't. We thought of that and what happens is because of ripple and noise created by the motor/ESC, the circuit within the servo gets damaged so it's not a good approach. Anyway, because we can readily identify this as the source of the damage, we won't cover it as a warranty repair.
Finally, if you haven't come across it, this video by a customer may help.